Controller



CONTROLLER Filed July 19, 1938 Inverfi tor:

' JohnT-il'ritiz, 'byX His A to r ey.

J. F. TRITLE 2,185,044

Patented Dec. 26, 1939 ATENT OFFICE CONTROLLER John F. Tritle, Erie, Pa., assignor to General Electric Company, a corporation of New York Application July 19, 1938, Serial No. 220,013

8 Claims.

My invention relates to controllers, more particularly to a mechanical interlock for a controller, and has for an object the provision of a device of this character which is reliable in opera- 5 tion, simple, and inexpensive to manufacture.

In connection with electrically driven trucks, hoists, and other machinery which may be reversed from a forward speed to a reverse speed, it is generally desirable to provide means for preventing the operator from throwing the controller into a reverse position without first applying the brakes. Without such preventative means, the driving motors are subjected to severe strains and overloading, and the operators find that the motors and equipment have deteriorated rapidly and that early replacement or repairs are necessary.

Accordingly, in the preferred embodiment of my invention, I have provided, for a conventiona1 reversing controller, an interlock comprising a pair of projecting members secured directly to a switching shaft of the controller, a pivoted locking member having a pair of angularly spaced arms or stops cooperating with the projecting members and arranged to be rotated thereby to a locking position, and a pivoted bar member for resetting the locking member. When the switching shaft of the controller is rotated from a neutral position in either direction to an operating position, one of the projecting members by a cam action causes the locking member to turn to a locking position, whereby the switching shaft is prevented from being moved in the reverse direction beyond the neutral position. Before the switching shaft may be rotated to the other operating position, it is necessary to first reset the locking member by applying a braking means which is arranged to actuate the resetting member. Upon braking, 40 the locking member is forced back to an unlocked position; thereupon the controller may be reversed. Thus, the necessity for braking before reversing is brought to the operators attention very pointedly, and he then may proceed to operate the machine in a correct manner.

For a more complete understanding of my invention, reference should be had to the accompanying drawing in which Fig. 1 is an eleva tional view of the controller embodying my invention; Fig. 2 is a left-side view of Fig. 1 showingthe interlocking mechanism of the controller in an unlocked position; Fig. 3 is an elevational view of the controller in section taken along the line 3-3 of Fig, 1; Fig. 4 is a left side view of Fig. 1 showing the interlocking mechanism in a locking position; Fig. 5 is a fragmentary elevational view of the left side of Fig. 1 showing the operation of the resetting member; and Fig. 6 is a perspective view of the locking member and the unitary star wheel and projecting members of the interlocking mechanism.

Referring to the drawing, I have shown my invention in one form as applied to a conventional type controller II] which may have therein a series of switching cams (not shown) carried by a switching shaft l I extending longitudinally of the controller l0 and suitably journaled at each end thereof in the end plates l2 and 13. The controller It] may be actuated by a suitable control lever M secured to a shaft [5 which is journaled in the end plate l2 of the controller. As shown in Fig. 3, the shaft l5 has secured thereto a segmental gear or gear sector 16 which is meshed with an operating pinion I'I secured at one end of the switching shaft II, the control lever It enabling the switching shaft II to be rotated in either direction through the gears l6 and ll for operating the cams that perform the required switching. By moving the controller lever l4 forward or backward from a central or neutral position, the controller switching mechanism may be set to several forward or reverse speed settings as desired.

Referring now to Fig. 2, the switching shaft ii is shown projecting through the end plate l3 of the controller l0 and having keyed thereon, held by means of a nut I8 and lock washer 19, a star wheel 20. Pivoted on a pin 2| extending from the end plate l3 of the controller HI and restrained thereon by a cotter pin 22 is a pawl 23 having a roller 24 pinned at the end thereof on a pin 25 and held in contact with the star wheel 20 by a compression spring 26. The force of the spring 26 supported between the pawl 23 and a seating projection 21 from the end plate l3 biases the pawl roller 24 into one of the several setting notches 28 in the star wheel 20.

In Fig. 2 the pawl 23 is shown maintaining the star wheel 20 in a neutral position ready for rotation in either direction to the several operating positions. Adjacent each of the axial faces of the star wheel 20, I have provided the projecting members 29 and 30 which I prefer to form as a unitary structure With the star wheel as shown in Fig. 6, although it is obvious that the projections 29 and 36 may be separate from the star wheel 29 and individually keyed to the switching shaft ll. Pivotally fastened above the switching shaft H on a pin 3|. extending from the end plate l3 and restrained thereon by a spring washer 32 and cotter pin 33 is a locking member having two arms 35 and 36 forming stops angularly spaced apart and arranged to coperate with the projections 29 and 30 thereadjacent. I prefer again to form the locking member 34 as a unitary piece shown in Fig. 6, having the two locking arms and 36 extending below the axial line of the member 34 joined by a sleeve portion 31 and having an additional projecting portion 38 extending thereabove which forms part of the resetting or unlocking mechanism to be described hereinafter.

At the top of the end plate l3 above the lockmember l have provided a pivot pin 39 having mounted for rotation and retained thereon by a cotter pin '55? a pivoted resetting lever 45 which is provided with a notch 42 on its bottom surface adapted to cooperate with the upper curved end of the resetting projection 38 for returning the locking member 34 to an unlocked position. At the left hand end of the pivoted resetting lever ll, I have provided a spring extending between a seating projection on the end plate i3 and a spring seat 45 on the lower surface of the resetting lever 41 for biasing the pivoted lever above and out of contact with the locking member 34. Fastened at the other end of the resetting lever 4| is a brake rod at which may be connected directly or through a spring to suitable braking means B which... when actuated, causes the notched portion lii of the resetting lever 4! to be pressed downwardly against the resetting projection 33 of the locking member 34. As shown in Fig. 5, the resetting projection 38 is forced to slide to the center of the notch 42, and the locking member is returned to its central or unlocked position from its locked position (shown in Fig. 4).

In operation of the controller, starting from a neutral control position as shown in Fig. 2, the controller lever M may be moved to an operating position, and through the gears I 6 and El, the star wheel 23 on the switching shaft H may be rotated an amount in a counterclockwise dinection. so that the spring-biased pawl is forced out of the neutral notch in the star wheel 23 to an operating notch as shown in Fig. i. The controller [0 then causes the motor controlled to operate at a fractional part of its forward speed, appropriate switching having taken place in the cam-operated switching mechanism of the controller. Initially, the locking member 34 was in a central unlocked position (shown in Fig. 2) and the star wheel 20 and the projections 29 and 30 could have been rotated to the operating positions in either direction. Revolving the star wheel 20 and. the projections 29 and 33 in a counter-clockwise direction, as described above, causes the locking member 34 to be tilted in the same direction about its pivot pin 3?! to a locked position by the cam action of the projection 29 against the lower end of the locking arm 35 (shown in Fig. 4).

With the locking member 34 held in the locked position by the spring washer 32, the star wheel 28 may be rotated counter-clockwise to the last operating notch to bring the motor up to full speed, or it be returned to the initial neutral position. However, the tilted locking mem-- ber will now prevent the controller from being passed through the neutral position to a reverse operating position, the locking arm 36 of the locking member 34 acting as a stop for preventing the movement of the projection 30 beyond the neutral control position.

To reverse the controller i t, the operator must return the control lever 14 to the neutral position and apply the braking means B. Application of the braking means B causes an upward pull to be exerted on the brake rod 46, and the notched portion 42 of the resetting member 4| is pressed against the resetting projection 38 of the locking member 34, the unlocking being effected by forcing the locking member 34 back to the central position (shown in Fig. 2). The controller it may then be moved to a reverse operating position, since the locking arm 36 is disposed to slide over the projection 33 with a cam action that causes the locking member 34 to be tilted in a clockwise direction, ready to stop the controller H! at the neutral control position should an attempt be made to return to a forward speed. This interlocking feature continually forces upon the operators attention the correct control sequence and eliminates the consequences of forgetfulness.

It may here be noted that the locking member 34 can only be returned to the central position from a tilted position when the controller is in a neutral control position because the curved edges of the projections 29 and 30 prevent the locking member 34 from otherwise being returned. Likewise, by connecting the brake rod Mi directly to the braking means B without an intervening spring therebetween, the operator is required first to return the controller It] to a neutral control position before the braking can be effected, since the tilted locking member 34 held so by one of the projections 29 or 30 would prevent the resetting lever 4i from being moved to apply the brake. Obviously, the brake connections are a matter of choice depending upon the control that is desired.

While I have shown a particular embodiment of my invention, it will be understood of course that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. An electrical controller comprising a rotatable switching shaft mounted for rotation from a neutral position in either direction to an opcrating position, switching means operable by said shaft, a pair of projections on said shaft, a pivoted member having a pair of stops adjacent said projections on opposite sides of said shaft, said member being turned from a central position to a tilted position by engagement of one of said projections with one of said stops when said shaft is turned from said neutral position either direction whereby the other of said stops is positioned to engage the other of said projections to prevent movement of said shaft in the opposite direction through said neutral position, and auxiliary means for returning said pivoted member to said central position.

2. An electrical controller comprising a rotatable switching shaft mounted for rotation from a neutral position in either direction to an operating position, switching means operable by said shaft, means including a pair of projections on said shaft, a pivoted member having a pair of stops adjacent said projections on opposite sides of said shaft, said member being turned from a central position to a tilted position by'engagcment of one of said projections with one of said stops when said shaft is turned from said neutral position in either direction whereby the other of said stops ispositioned to engage the other of said projections to prevent movement of said shaft in the opposite direction through said neutral position, auxiliary means for returning said pivoted member to said central position, and braking means arranged to operate said auxiliary means.

3. An electrical controller having an end plate comprising a rotatable switching shaft journaled in said end plate and extending therethrough for rotation from a neutral position in either direction to a plurality of operating positions, switching means on one side of said end plate operable by said shaft, and interlocking means on the other side of said end plate including a pair of projections on said shaft, a member pivoted on a pin extending from said plate, said pivoted member having a pair of arms angularly spaced from each other and projecting radially from said pin adjacent said projections on either side of said shaft, said member being arranged for rotation from a central position by a cam action of one of said projections on one of said arms to a tilted position when said shaft is revolved from said neutral position to any of said operating positions, whereby the other of said arms of said member is positioned to contact the other of said projections on its return movement for preventing said shaft from being revolved through said neutral position, and auxiliary means including a pivoted lever and an extending portion of said member for returning said member to a central position.

4. An electrical controller having an end plate comprising a rotatable switching shaft journaled in said end plate and extending therethrough for rotation from a neutral position in either direc tion to a plurality of operatin positions, switching means on one side of said end plate operable by said shaft, and interlocking means on the other side of said end plate including a pair of projections on said shaft, a member pivoted on a pin extending from said plate, said pivoted member having a pair of arms angularly spaced from each other and projecting radially from said pin adjacent said projections on either side of said shaft, said member being arranged for rotation from a central position by a cam action of one of said projections on one of said arms to a tilted position when said shaft is revolved from said neutral position to any of said operating positions, whereby the other of said arms of said member is positioned to contact the other of said projections on its return movement for preventing said shaft from being revolved through said neutral position, means including a frictional holding device for restraining said pivoted 1nember in any of said positions to which it is turned, and auxiliary means including a pivoted lever and an extending portion of said member for returning said member to a central position.

5. An interlock for a rotatable element, said rotatable element being mounted for rotation from a neutral position in either direction to an operating position, comprising a plurality of projections on said rotatable element, a pivoted looking member having a pair of stops extending adjacent said projections, one of said stops cooperating with one of said projections in either direction of rotation of said rotatable element from said neutral position to an operating position to tilt said locking member from a central position to a locking position whereby another'of said stops is positioned to contact another of said projections for preventing movement of said rotatable element through said neutral position when said rotatable element is returned to said neutral position from said operating position, and auxiliary means for moving said locking member back to said central position for permitting movement of said rotatable element to another of said operating positions thereafter.

6. An electrical controller having an end plate comprising a rotatable switching shaft journaled in said end plate and extending therethrough for rotation from a neutral position in either direction to a plurality of operating positions, switching means on one side of said end plate operable by said shaft, and interlocking means on the other side of said end plate including a pair of projections on said shaft, a member pivoted on a pin extending from said plate, said pivoted member having a pair of arms angularly spaced from each other and projecting radially from said pin adjacent said projections on either side of said shaft, said member being arranged for rotation from a central position by a cam action of one of said projections on one of said arms to a tilted position when said shaft is revolved from said neutral position to any of said operating positions, whereby the other of said arms of said member is positioned to contact the other of said projections on its return movement for preventing said shaft from being revolved through said neutral position, means including a frictional holding device for restraining said pivoted member in any of said positions to which it is turned, auxiliary means including a pivoted lever and an extending portion of said member for returning said member to a central position, said auxiliary means moving said locking member back to said central position for permitting movement of said rotatable shaft to another of said operating positions thereafter, and braking means connected to said auxiliary means for operation thereof.

'7. An interlock for a rotatable element, said rotatable element being mounted for rotation from a neutral position in either direction to a plurality of operating positions, comprising a pair of projections on said rotatable element, a pivoted member having a pair of arms angularly spaced from each other and projecting adjacent said projections on either side of said rotatable element, said member being arranged for rotation from a central position to a tilted position by engagement of one of said projections with one of said arms when said rotatable element is turned from said neutral position to any of said operating positions, whereby the other of said arms of said member is positioned to contact the other of said projections on its return movement for preventing said rotatable element from being turned through said neutral position, and auxiliary means for returning said pivoted member to said central position for permitting movement of said rotatable element to any of said operating positions.

8. An interlock for a rotatable element, said rotatable element being mounted for rotation from a neutral position in either direction to a plurality of operating positions, comprising a pair of projections on said rotatable element, a pivoted member having a pair of arms angularly spaced from each other and projecting radially adjacent said projections on either side of said rotatable element, said member being arranged for rotation from a central position by a cam action of one of said projections on one of said arms to a tilted position when said rotatable element is turned from said neutral position to any of said operating positions, whereby the other of said arms of said member is positioned to contact the other of said projections on its return movement for preventing said rotatable element from being turned through said neutral position, and auxiliary means including a pivoted lever and an extending portion of said member for returning said member to said central position.

JOHN F. TRITLE. 

